Project description:CD8+ tumor-infiltrating lymphocytes with a tissue-resident memory T (TRM) cell phenotype are associated with favorable prognosis in patients with triple negative breast cancer (TNBC). However, the relative contribution of CD8+ TRM cells to anti-tumor immunity and immune checkpoint blockade efficacy in breast cancer remains unknown. Here, we show that intratumoral CD8+ T cells in murine mammary tumors transcriptionally resemble those from triple-negative breast cancer patients. Phenotypic and transcriptional studies established two intratumoral sub-populations: one more enriched in markers of terminal exhaustion (TEX-like) and the other with a bona-fide resident phenotype (TRM-like). Treatment with anti-PD-1 and anti-CTLA-4 therapy resulted in a expansion of these intratumoral populations, with the TRM-like subset displaying significantly enhanced cytotoxic capacity. Importantly, we demonstrate that it is the TRM-like CD8+ T cells can provide local immune protection against mammary tumor re-challenge and that a gene signature from remaining TRM-like CD8+ T cells extracted from tumor-free tissue was significantly associated with improved outcomes in human TNBC patients treated with checkpoint inhibition. Overall, our data suggest that CD8+ T cells with a tissue resident phenotype play a critical role in response to local immunosurveillance and responses to immune checkpoint blockade in breast cancer
Project description:<p>Plasmacytoid dendritic cells (pDC) are a subset of dendritic cells with unique immunophenotypic properties and functions. While their role in antiviral immunity through production of type I interferons is well-established, their contributions to anti-tumor immunity are less clear. While some evidence demonstrates that pDC in the tumor microenvironment (TME) may drive CD4+ T cell to become <a href="https://www.ncbi.nlm.nih.gov/gene/50943">Foxp3</a>+ T regulatory cells, little is understood about the relationship of pDC with cytotoxic CD8+ T cell, the key player in antitumor immune responses.</p> <p>In this study, we perform comprehensive immunophenotyping and functional analysis of pDC from the TME and draining lymph nodes of patients with head and neck squamous cell carcinoma (HNSCC) and identify a novel pDC subset characterized by expression of the TNF receptor superfamily member <a href="https://www.ncbi.nlm.nih.gov/gene/?term=7293">CD134 (OX40)</a>. We show that OX40 expression is expressed on intratumoral pDC in both humans and mice in a tumor-model specific fashion and that this subset of pDC enhances tumor associated-antigen (TAA)-specific CD8+ T cell responses. Through transcriptomic profiling of OX40-expressing pDC from the TME, we further characterize gene signatures unique to this pDC subset that support its role as an important immunostimulatory immune population in the TME.</p>
Project description:TGFb signaling is a major pathway associated with poor clinical outcome in patients with
advanced metastatic cancers and non-response to immune checkpoint blockade, particularly in the immune-excluded tumor phenotype. While previous pre-clinical studies demonstrated that converting tumors from an excluded to an inflamed phenotype and curative anti-tumor immunity require attenuation of both PD-L1 and TGFb signaling, the underlying cellular mechanisms remain unclear. Recent studies suggest that stem cell-like CD8 T cells (TSCL) can differentiate into non-exhausted CD8 T effector cells that drive durable anti-tumor immunity. Here, we show that TGFb and PD-L1 restrain TSCL expansion as well as replacement of progenitor exhausted and dysfunctional CD8 T cells with non-exhausted IFNghi CD8 T effector cells in the tumor microenvironment (TME). Blockade of TGFb and PD-L1 generated IFNghi CD8 T effector cells with enhanced motility, enabling both their accumulation in the TME and increased interaction with other cell types. Ensuing IFNg signaling markedly transformed myeloid, stromal, and tumor niches to yield a broadly immune-supportive ecosystem. Blocking IFNg completely abolished the effect of anti-PD-L1/ TGFb combination therapy. Our data suggest that TGFb works in concert with PD-L1 to prevent TSCL expansion and replacement of exhausted CD8 T cells with fresh CD8
T effector cells, thereby maintaining the CD8 T cell compartment in a dysfunctional state.
Project description:Through a diversity of functional lineages, cells of the innate and adaptive immune system either drive or constrain immune reactions within tumors. Thus, while the immune system has a powerful ability to recognize and kill cancer cells, this function is often suppressed preventing clearance of disease. The transcription factor (TF) BACH2 controls the differentiation and function of multiple innate and adaptive immune lineages, but its role in regulating tumor immunity is not known. Here, we demonstrate that BACH2 is required to establish immunosuppression within tumors. We found that growth of subcutaneously implanted tumors was markedly impaired in Bach2-deficient mice and coincided with intratumoral activation of both innate and adaptive immunity but was dependent upon adaptive immunity. Analysis of tumor-infiltrating lymphocytes in Bach2-deficient mice revealed high frequencies of CD4+ and CD8+ effector cells expressing the inflammatory cytokine IFN-γ. Lymphocyte activation coincided with reduction in the frequency of intratumoral CD4+ Foxp3+ regulatory T (Treg) cells. Mechanistically, Treg-dependent inhibition of CD8+ T cells was required for BACH2-mediated tumor immunosuppression. These findings demonstrate that BACH2 is a key component of the molecular programme of tumor immunosuppression and identify a new target for development of therapies aimed at reversing immunosuppression in cancer. Analysis of tumor-infiltrating lymphocytes in Bach2-deficient mice revealed high frequencies of CD4+ and CD8+ effector cells expressing the inflammatory cytokine IFN-γ. Lymphocyte activation coincided with reduction in the frequency of intratumoral CD4+ Foxp3+ regulatory T (Treg) cells. Mechanistically, Treg-dependent inhibition of CD8+ T cells was required for BACH2-mediated tumor immunosuppression.
Project description:Immunotherapy efficacy is limited in melanoma, and combinations of immunotherapies with other modalities have yielded limited improvements but also adverse events requiring cessation of treatment. In addition to ineffective patient stratification, efficacy is impaired by paucity of intratumoral immune cells (itICs)—thus, effective strategies to safely increase itICs are needed. We report that dietary administration of L-fucose induces fucosylation and cell surface enrichment of the MHC-II protein HLA-DRB1 in melanoma cells, triggering CD4+T cell-mediated increases in ItICs and anti-tumor immunity, enhancing immune checkpoint blockade responses. Melanoma fucosylation and fucosylated HLA-DRB1 associate with intratumoral T cell abundance and anti-PD1 responder status in patient melanoma specimens, suggesting the potential use of melanoma fucosylation as a strategy for stratifying patients for immunotherapies. Our findings demonstrate that fucosylation is a key mediator of anti-tumor immunity, and importantly, suggest that L-fucose is a powerful agent for safely increasing ItICs and immunotherapy efficacy in melanoma.
Project description:Immunotherapy efficacy is limited in melanoma, and combinations of immunotherapies with other modalities have yielded limited improvements but also adverse events requiring cessation of treatment. In addition to ineffective patient stratification, efficacy is impaired by paucity of intratumoral immune cells (itICs)—thus, effective strategies to safely increase itICs are needed. We report that dietary administration of L-fucose induces fucosylation and cell surface enrichment of the MHC-II protein HLA-DRB1 in melanoma cells, triggering CD4+T cell-mediated increases in ItICs and anti-tumor immunity, enhancing immune checkpoint blockade responses. Melanoma fucosylation and fucosylated HLA-DRB1 associate with intratumoral T cell abundance and anti-PD1 responder status in patient melanoma specimens, suggesting the potential use of melanoma fucosylation as a strategy for stratifying patients for immunotherapies. Our findings demonstrate that fucosylation is a key mediator of anti-tumor immunity, and importantly, suggest that L-fucose is a powerful agent for safely increasing ItICs and immunotherapy efficacy in melanoma.
Project description:Immunotherapy efficacy is limited in melanoma, and combinations of immunotherapies with other modalities have yielded limited improvements but also adverse events requiring cessation of treatment. In addition to ineffective patient stratification, efficacy is impaired by paucity of intratumoral immune cells (itICs)—thus, effective strategies to safely increase itICs are needed. We report that dietary administration of L-fucose induces fucosylation and cell surface enrichment of the MHC-II protein HLA-DRB1 in melanoma cells, triggering CD4+T cell-mediated increases in ItICs and anti-tumor immunity, enhancing immune checkpoint blockade responses. Melanoma fucosylation and fucosylated HLA-DRB1 associate with intratumoral T cell abundance and anti-PD1 responder status in patient melanoma specimens, suggesting the potential use of melanoma fucosylation as a strategy for stratifying patients for immunotherapies. Our findings demonstrate that fucosylation is a key mediator of anti-tumor immunity, and importantly, suggest that L-fucose is a powerful agent for safely increasing ItICs and immunotherapy efficacy in melanoma.
Project description:Immunotherapy efficacy is limited in melanoma, and combinations of immunotherapies with other modalities have yielded limited improvements but also adverse events requiring cessation of treatment. In addition to ineffective patient stratification, efficacy is impaired by paucity of intratumoral immune cells (itICs)—thus, effective strategies to safely increase itICs are needed. We report that dietary administration of L-fucose induces fucosylation and cell surface enrichment of the MHC-II protein HLA-DRB1 in melanoma cells, triggering CD4+T cell-mediated increases in ItICs and anti-tumor immunity, enhancing immune checkpoint blockade responses. Melanoma fucosylation and fucosylated HLA-DRB1 associate with intratumoral T cell abundance and anti-PD1 responder status in patient melanoma specimens, suggesting the potential use of melanoma fucosylation as a strategy for stratifying patients for immunotherapies. Our findings demonstrate that fucosylation is a key mediator of anti-tumor immunity, and importantly, suggest that L-fucose is a powerful agent for safely increasing ItICs and immunotherapy efficacy in melanoma.
Project description:Cancer immunotherapy with immunostimulatory antibodies targeting the CTLA-4 or PD-1/PD-L1 pathways has demonstrated its efficacy in variable proportions of cancer. For metastatic colorectal cancer (mCRC) it appeared that only the small subgroup of patients with MSI-H tumors (microsatellite instability-high phenotype) had a clinically meaningful response to the anti-PD-1- L1 antibodies. In the majority group of non-MSI-H CRC (90-95% of patients), current research expect that additional means would be able to render the tumor "immunogenic" (like MSI-H CRC) and increase the intratumoral immune infiltrate which is the prerequisite to observe a benefit from PD1-PD-L1 inhibitors. Combinations of immune checkpoint inhibitors and procedures that increase intratumoral immune responses, such as targeted therapy, are actively explored.
Project description:Analyses of healthy tissue reveal signatures that identify resident memory CD8+ T cells (TRM), which survey tissues without recirculating. The density of TRM-phenotype cells within solid tumors correlates favorably with prognosis, suggesting that intratumoral residents control cancer. However, residence has not been directly tested and intratumoral TRM-phenotype cells could instead reflect aspects of the microenvironment that correlate with prognosis. Using a breast cancer model, we found that conventional TRM markers do not inform the tumor residence of either bystander or tumor-specific cells, which exhibit further distinct phenotypes in the tumor microenvironment and healthy mammary tissue. Rather, tumor-specific, stem-progenitor CD8+ T cells migrate to tumors and become resident while acquiring select markers of exhaustion. These data indicate that tonic antigen stimulation and the tumor environment drive distinct programs of residence compared to healthy tissues and that tumor immunity is sustained by continued migration of tumor-specific stem cells.